Some embodiments relate to a cosmetic composition containing an extract of slender-beaded coral weed and at least one extract of everlasting.
Some embodiments also relate to the cosmetic use of a composition including an extract of slender-beaded coral weed and at least one extract of everlasting. In particular, some embodiments relate to the nontherapeutic cosmetic use of a composition including an extract of slender-beaded coral weed and at least one extract in a nontherapeutic antiaging cosmetic treatment.
Some embodiments also relate to the cosmetic use of a composition including an extract of slender-beaded coral weed and at least one extract of everlasting in a nontherapeutic cosmetic treatment for protecting the skin against external attack.
Some embodiments also relate to a nontherapeutic cosmetic treatment process including the application of a cosmetic composition including an extract of slender-beaded coral weed and at least one extract of everlasting.
Some embodiments also relate to a cosmetic care kit especially including a cosmetic composition including an extract of slender-beaded coral weed and at least one extract of everlasting.
Some embodiments provide an application especially in the cosmetic and/or dermatological fields.
In the description below, the references in square brackets ([ ]) refer to the list of references presented at the end of the text.
The skin has a very complex architecture. As a barrier between the external environment and the internal medium of our body, its functioning serves two purposes: ensuring communication between the organism and the external environment, and protecting it against attack [1].
With age, the various cutaneous structures are modified both morphologically and functionally. The main consequences are a decline in the defense, cicatrization, perception and thermoregulation functions and also the establishment of a chronic inflammatory state corresponding to an increase in the number of macrophages and persistent cutaneous dryness [2].
In the epidermis, its turnover passes from 21 days to 40 days, which accounts for the negative impact on cicatrization and tissue repair [3]. The keratinocytes become smaller and fewer in number. The cell turnover slows down and the cohesion between the dermis and the epidermis becomes attenuated.
By its constant turnover, the epidermis is the physical barrier against chemical, physical and bacterial attack. The epidermal keratinocytes undergo morphological and biochemical changes when they migrate from the basal layer to the spinous and granulous layers to form the stratum corneum. Various proteins characterize each layer of the epidermis: keratins 5 and 14 are the main keratins of the basal layer, whereas keratins 1, 2 and 10 are expressed by the suprabasal keratinocytes. Certain proteins that are associated with differentiation, such as involucrin, loricrin and filaggrin, are expressed solely in the differentiated layers of the epidermis [4, 5, 6].
The cornification process is initiated in the stratum spinosum with the expression of the proteins involucrin [7], periplakin [8] and envoplakin [9]. Initially, these two members of the plakin family (periplakin and envoplakin) form a complex with involucrin and are attached to the inner surface of the plasma membrane [10], forming an assembly [11]. The recruitment and binding of periplakin and envoplakin to the lipid bilayer may require the presence of calcium. These three proteins (envoplakin, involucrin and periplakin) are crosslinked by transglutaminase 1, the enzymatic activity of which is calcium-dependent. Continuous formation of the cornified envelope may require the production of lamellar bodies in the stratum granulosum. Secretion of the content of the lamellar bodies gives the skin its impermeability and protects it against bacteria.
The main component of the cornified envelope is loricrin. This protein represents more than 80% of the mass of proteins of the cornified envelope and is expressed in the stratum granulosum [12]. The synthesis of loricrin may require a calcium concentration of about 0.1 mM. During the process of formation of the cornified envelope, loricrin is crosslinked with itself and with the members of the SPRR (small proline rich repeat) family [13, 14]. The addition of calcium to keratinocytes in primary culture greatly increases the expression of SPRRs. They are thus crosslinked with loricrin via the Nε-(γ-glutamyl)lysine (isopeptide) bridges by transglutaminases 1 and 3 [13, 15]. During the final process of formation of the cornified envelope, the loricrin-SPRR assembly is transported to the cell membrane and attached to the periplakin-involucrin-evoplakin assembly [12]. The final proteins incorporated in the cornified envelope are the members of the “late cornified envelope” (LCE) family [16, 17].
Within the epidermis, the keratinocytes have different calcium needs. The keratinocytes of the basal layer may require very low calcium concentrations allowing the division of stem cells which ensure the epidermal renewal. Whereas high calcium concentrations may be required for the differentiation program resulting in the formation of corneocytes and of the cornified envelope. In order for the keratinocytes to encounter these various concentrations, a calcium gradient is constructed within the epidermis. In elderly people, the calcium gradient is greatly perturbed. Specifically, in young people or young adults, a calcium peak is clearly observed in the upper layer of the stratum granulosum, whereas, in elderly people, calcium is distributed homogeneously in all the layers of the epidermis [18].
Filaggrin is produced by the granulous keratinocytes in the form of a precursor known as profilaggrin, which includes 10-12 filaggrin units. It is the major component of keratohyalin granules. During the transition of the granules to the cornified envelope, profilaggrin is rapidly dephosphorylated and cleaved by certain proteases such as caspase-14, bleomycin hydrolase and calpain 1 [19, 20, 21] to generate filaggrin monomers [21]. These filaggrin monomers associate with keratin filaments and are suspected to induce the formation of the fibrous matrix of the corneocytes [22]. In the cornified cells, filaggrin is degraded into free amino acids and other components of the natural skin moisturizing factor. These free amino acids may be necessary for photoprotection of the skin (urocanic acid) and also the acidification and moisturization (pyrrolidonecarboxylic acid) of the stratum corneum [21, 23, 24].
With age, the turnover of the keratinocytes is considerably reduced and the protein composition of the cornified envelope responsible for the barrier function is profoundly modified. It is thus of importance to restore the keratinocyte proliferation and also their differentiation potential for the purpose of restoring the epidermal homeostasis and the barrier function of the skin which are perturbed by aging of the skin.
Moreover, with age, the skin loses its firmness and its elasticity, which may especially be the cause of the appearance of wrinkles both on the face and over the entire body.